WO2005035029A1

WO2005035029A1 - Injection device comprising a needle cover

Info

Publication number: WO2005035029A1
Application number: PCT/CH2004/000617
Authority: WO
Inventors: Edgar Hommann; Hans Himbert; Ulrika Vejbrink
Original assignee: Tecpharma Licensing Ag
Priority date: 2003-10-16
Filing date: 2004-10-08
Publication date: 2005-04-21
Also published as: US20070078382A1; AU2004279650A1; EP1680162A1; JP2007521845A; CN1867368B; CN1867368A; DE10348185A1; US7566324B2

Abstract

An injection device comprising a needle cover (15) includes: a casing (1, 5) which forms a receptacle for a container containing an injectable product or forms said container itself, a conveying means for said product, and a needle holder (10) comprising an injection needle (11) which is or can be connected fluidically to the container by means of said needle holder (10). The said needle cover (15) is mounted by said casing (1, 5) such that it can be moved in the proximal direction, against a restoring force, from a protecting position, past an injection position, into an assembling position. In the protecting position, the needle cover (15) extends beyond a distal needle tip of said injection needle (11), and in said injection position is short of said needle tip. In the assembling position, the needle cover (15) allows access to the needle holder (10), such that the needle holder (10) can be gripped and connected to the casing (1, 5) and/or detached from the casing (1, 5).

Description

Injection Device Comprising a Needle Cover

The invention relates to an injection device comprising a needle cover for an injection needle which may be or is already affixed to a front, distal end of the injection device. The injection device is preferably used in self-administering an injectable product, for example insulin, a growth hormone or an osteoporosis medicine. The injection device can in particular be an injection pen.

The injection needle of an injection device poses a danger of injury on the one hand, for example when exchanging the injection needle, and on the other arouses fear (needle phobia) in many patients who administer the product to themselves by injection, which can very well be the cause of an incorrect injection or at least a less than optimal injection; In order to reduce fear of the injection needle, injection devices are often provided with a needle blind which surrounds the needle in a protecting position, such that the user of the injection device in question cannot see the needle. The needle blind is usually held in the protecting position by a mechanical spring. For injecting, the user places the injection device onto the skin at the injection point and presses it against the skin, such that the needle blind is moved out of the protecting position, against the force of the spring, and the injection needle is simultaneously introduced into the body tissue. When the injection needle is removed from the body tissue, the needle blind automatically moves back into the protecting position due to the restoring force of the spring. In addition to the needle blind, a needle protection for injection devices is also known which is at least not primarily intended solely as a blind but as protection for the user against injuries from the injection needle. In the protecting position cited, the needle protection is locked and cannot be moved in the proximal direction by a pressure force alone acting in the proximal direction but only by destruction or by conscious, additional handling which releases a latch which is active in the protecting position. The needle protection can in principle expose the needle to view or, however, can also have the capacity of a blind, in addition to the function of protecting access. A needle protection sole is known for example from US-PS 6,033,387 for an injection device embodied as a simple syringe. The needle protection encases the syringe completely and forms, so to speak, an outer casing for the syringe as a whole. When, after an injection, the needle protection has been moved into its protecting position by hand, it cannot be moved back out of the protecting position, or at least cannot be moved back into an assembling position until the syringe has been removed. In particular, there exists no injection position for the needle protection from which it automatically moves into the protecting position when the pressure in the distal direction is relieved.

Injection devices such as the invention relates to in particular comprise a container holder into which a container filled with the product to be injected is inserted and, once consumed, replaced by a new container. In many cases, the container is an ampoule filled by the product manufacturer which is sealed at one end by an axially shifting piston and at another end by a sealing element. Since such injection devices are provided for an extended period of use with a number of consecutive product containers, the injection needles are also exchanged from time to time, for example together with the container. To this end, the injection needle is affixed to a needle holder connected to the injection device. When the needle holder is connected to the injection device, the injection needle pierces the sealing element of the container via a proximal needle tip, such that the fluidic connection between the interior of the container and the injection needle is established.

Needle covers of devices of this type, such as are known for example from DE 197 55 125 Al and DE 100 09 816 Al, have a drawback that they cannot be connected to the injection device until the needle holder has already been connected to the injection device. This has the result that the user has to affix the needle cover to the injection device while the injection needle is exposed and therefore has to work against the exposed injection needle, so to speak, when affixing the needle cover. Instead of the terms needle protection and needle blind, the term needle cover is used undifferentiated in the following, which— if nothing is said as to the protecting function or blind function - is intended to include both the needle blind alone and the needle access protection alone and furthermore the combination of needle access protection and needle blind.

It is an object of the invention to provide an injection device comprising a needle cover, in which the danger of a needle prick while affixing a needle holder to the injection device and/or detaching a needle holder from the injection device is reduced.

An injection device such as the invention relates to includes a casing which forms a receptacle for a container containing an injectable product or directly forms such a container itself. The injection device further includes a conveying means for the product, a needle holder including an injection needle and a needle cover. Preferably, the needle holder may be connected or is connected to the casing, irrespective of whether the casing forms the product container itself or, as preferred, the product container is a separate, preferably exchangeable container which the casing accommodates. In the case of a product container accommodated by the casing, it is in principle also conceivable that the needle holder may be connected or is connected directly to such a container. The injection needle is held by the needle holder such that it is fluidically connected to the inner space of the container when the needle holder is connected to the container or preferably to the casing. When the needle holder is connected in this way, the product is delivered out of the container through the injection needle by a conveying action of the conveying means.

The needle holder can in particular be formed like known needle holders in which injection needle is connected to the needle holder in a middle needle section, protrudes beyond the needle holder via a distal needle section and projects from the proximal side, i.e. on the side of the needle holder to be connected or being connected to the casing or the container, via a proximal needle section. The injection needle does not, however, necessarily have to comprise a projecting proximal needle section. The needle cover is mounted by the casing such that it can be moved back and forth in the distal and proximal direction. The needle cover is loaded with a restoring force in the distal direction. Influenced by the restoring force, it assumes a protecting position in which it protrudes in the distal direction beyond the distal tip of the injection needle, when the needle holder is connected to the casing or the container. The needle cover can be moved in the proximal direction, against the restoring force, out of the protecting position into an injection position, and in the proximal direction beyond the injection position into an assembling position. In the injection position, the distal tip of the injection needle protrudes beyond the distal end of the needle cover. In order to move the needle cover in the proximal direction, it must be loaded with a force opposing and exceeding the restoring force. Typically, such a force acts when the injection needle is introduced into a body tissue, namely due to the resistance of the surface of the tissue against which the needle cover is pressed during the injection. If, in the injection position, the force acting in the proximal direction abates, then the needle cover automatically moves back in the distal direction under the influence of the restoring force. In this respect, only the equilibrium of the forces, i.e. of the restoring force and the opposing force, prevails in the injection position. The injection position is therefore not fixedly predetermined, but depends on the depth of penetration of the injection needle during the injection. It is, however, defined in as much as that the injection needle can only penetrate into the tissue during the injection using its distal needle section which protrudes beyond the needle holder. The distal end of the needle cover and the distal end of the needle holder are therefore level during the injection.

In accordance with the invention, the needle cover can furthermore be moved against the restoring force into the assembling position. In the assembling position, it releases access to the needle holder, such that the needle holder can be gripped and connected to the casing and/or detached from the casing by hand. The needle cover can therefore be connected to the casing before attaching the needle holder, preferably even when assembling the injection device at the manufacturer's. The needle cover does not have to be removed to exchange the injection needle. In preferred embodiments, it is an integral component of the injection device and cannot even be detached from the injection device, i.e. from its casing, by the user, generally the patient administering the product to him/herself, which reduces the danger of incorrect assembly. In particular, however, the danger of injury from the injection needle while assembling and/or disassembling the needle holder, for example while exchanging the injection needle, is reduced, since the user does not have to assemble the needle cover when the injection needle is exposed.

In its assembling position, the needle cover is preferably sufficiently short of the distal end of the needle holder in the proximal direction that the user can comfortably grip the needle holder from the side, i.e. perpendicular to the longitudinal direction of the needle, with his or her fingers and perform the necessary handling for assembling and/or disassembling the needle holder.

In preferred embodiments, as already mentioned, the casing forms a receptacle for a product container which in an even more preferred embodiment is exchangeable. To this end, the casing includes a container holder which forms an accommodating chamber for the container. A stopper for the container is formed in the accommodating chamber, against which the container preferably contacts in the distal direction. It is furthermore preferred if the container holder secures the container in the accommodating chamber against movements perpendicular to the distal and/or proximal direction. The accommodating chamber is preferably open at a proximal end of the chamber, such that the container introduced in the distal direction into the accommodating chamber, up to the stopper. It would also, however, be possible to provide the accommodating chamber with the opening for the container at its distal end or, in principle, also on the side. Preferably, the container holder is dimensionally stable in its own right, i.e. not flexible but rigid.

In accordance with preferred embodiments, the needle cover is supported in the proximal direction on such a container holder, such that the restoring force acts between the needle cover and the container holder, preferably as an elasticity force. Instead of being directly supported on the container holder, the needle cover can in principle also be supported on another casing part of the injection device which is connected to the container holder. The needle cover is preferably guided sliding on the container holder, i.e. the container holder forms a sliding guide for the needle cover. A restoring means which generates the restoring force preferably generates the restoring force as an elasticity force. Preferably, due to its simplicity, the elasticity force is generated by a mechanical spring, for example by a spiral spring, which is biased, preferably pressurised, at least in the assembling position and injection position and preferably also in the protecting position. In principle, it would also be possible to generate the elasticity force by compressing a gas, preferably air.

In order to make assembling and/or disassembling the needle holder easier, the needle cover is prevented, in the assembling position, from moving in the distal direction by means of a locking means acting between the needle cover and the casing, such that the user does not have to hold the needle cover against the restoring force him/herself. For the lock, the casing is provided with a first locking element and the needle cover with a second locking element. When the needle cover is in the assembling position, the locking elements are in a locking mesh which holds the needle cover in the assembling position against the restoring force. A number of first and second locking elements, each in pairs, can be in a locking mesh. If a number of first and second locking elements are provided, it is preferred if two first locking elements and two second locking elements are provided and each first and second of the locking elements, in pairs, are in a locking mesh with each other. The two locking element pairs are expediently arranged on sides of the injection device which are diametrically opposite each other with respect to an axial. The locking mesh can be based solely on a frictional lock between the locking elements, however the locking mesh is preferably based on a positive lock, or as applicable a combined frictional and positive lock.

The injection device preferably includes an unlocking element which can be operated by the user and which, when operated, releases the locking mesh. The unlocking element can be directly formed by a sleeve body which preferably forms the needle cover, if for example the user can grip a sleeve section of such a sleeve body, in the assembling position. In addition to such a covering sleeve or sleeve-shaped covering body, the needle cover preferably includes an unlocking element which can be moved relative to such a covering sleeve or sleeve-shaped covering body. If a number of locking element pairs are provided, one such unlocking element is preferably provided per pair. The unlocking element is particularly preferably formed as a push- key which is pressed relative to the covering sleeve or sleeve-shaped covering body, in order to release the locking mesh.

In a preferred embodiment, at least one of the locking elements - particularly preferably, exactly one - can be moved out of locking mesh against an elasticity force and is automatically moved into the locking mesh due to the elasticity force when the needle cover is moved into the assembling position. Preferably, the at least one locking element which can be moved out of locking mesh against an elasticity force is itself elastic. Advantageously, it is dimensionally elastic, such that it simultaneously applies the elasticity force for pre-latching into the locking mesh itself and on the other hand exhibits the necessary rigidity for a positive lock. The elastic locking element is particularly preferably a bending tongue comprising either a projecting cam or a recess or breach into which the other locking element protrudes in the locking mesh.

The casing preferably includes a cladding structure which surrounds at least an axial section of the needle cover when the needle cover is in the assembling position. When the needle cover moves into the assembling position, at least said axial section of the needle cover enters the cladding structure of the casing. Preferably, the cladding structure surrounds a distal section of the container holder already cited, wherein an annular space remains between the cladding structure and the distal section of the container holder and at least said axial section of the needle cover is accommodated in said space, in its assembling position. Preferably, an axial section of the needle cover also protrudes into the cladding structure of the casing and the preferably formed annular space in the protecting position. In the assembling position, it is preferably completely or almost completely accommodated in the annular space, such that it closes flush with the cladding structure of the casing or only protrudes beyond the distal end of the cladding structure of the casing by a short axial section. The restoring means in particular can be accommodated in the annular space.

It may also be noted with respect to the conveying means that, in a preferred embodiment, it includes a piston accommodated in the container, wherein a stroke of said piston delivers product from the container through the injection needle. The piston stroke preferably points in one of the axial directions, particularly preferably in the distal direction.

The injection device is preferably one which allows a predetermined product dosage or a number of respectively selectable product dosages to be administered a number of times. For this purpose, such an injection device includes a dosing means which meshes with the conveying means, preferably in a mechanical mesh which causes the product dosage to be set by a dosing movement of the dosing means, wherein said product dosage can be conveyed by means of the conveying means when the conveying means is operated. In a preferred embodiment of the conveying means as a piston conveying means, this can in particular be the length of the piston stroke or, in the case of a piston stroke which is for example always of the same length, the setting of a slight gap between a rear side of the piston and an end of a piston rod axially facing the rear side of the piston, which initially travels the slight gap up to the piston when a conveying stroke is performed, and then slaves the piston for the remaining stroke.

In addition to the injection device as such, the invention also has as its subject a method for affixing a needle holder, which holds an injection needle, to a distal end of an injection device, and furthermore a method for detaching a needle holder, which holds an injection needle, from a distal end of an injection device. The injection device is provided with a needle cover which in a protecting position surrounds the injection needle up to and beyond a distal tip of the needle when the needle holder is affixed to the injection device, and which can be shifted out of the protecting position against a restoring elasticity force, towards a proximal end of the injection device beyond the distal end of the needle holder, up to an assembling position.

When affixing the needle holder, the needle cover is moved from the protecting position into the assembling position in a first step, and a locking mesh is established which holds the needle cover in the assembling position, against the elasticity force. Preferably, the locking mesh is established automatically when the needle cover has reached the assembling position. While the needle cover is situated in the locked assembling position, the needle holder is affixed to the distal end of the injection device. It is for example screwed onto the distal end of the injection device. The needle holders are usually provided with a protecting cap which protectively surrounds the needle section distally protruding beyond the needle holder, and on the other hand protects the user from needle pricks. When using such a needle holder, said protecting cap is removed once the needle holder has been affixed, such that the injection needle protrudes exposed. If, furthermore, another protecting cap also surrounds the needle holder, then this other protecting cap is also removed. The locking mesh is then released, such that the needle cover is automatically moved into the protecting position by the influence of the restoring elasticity force.

For detaching the needle holder, the needle cover is moved from the protecting position into the assembling position - and therefore, preferably automatically, into the locking mesh - in a first step, as for affixing the needle holder. With the needle cover in the assembling position, the needle holder is detached from the distal end of the injection device, and disposed of. A protective cap is affixed, preferably plugged, onto the needle holder, preferably before the needle holder is detached, while the needle cover is in the assembling position, in order to protect the user from needle pricks.

In an other embodiment of the present invention, a guiding means is provided on an interior side of a sleeve serving as needle cover, to guide when the injection needle or a cap for the injection needle is placed onto or removed from the product container. To this end, grooves or projections can be provided, along which corresponding, complementary grooves or projections on an injection needle unit or cap can be guided onto the product container or its holder. In another embodiment, it is also possible to arrange the injection needle unit or the cap in a particular rotational position with respect to the product container. The rotational position is maintained by the guiding means. The needle unit or the cap is inserted into or attached to the guide of the sleeve in this position. By retracting the sleeve, together with the needle unit or cap, in the axial direction towards the product container, the needle unit or cap is then guided onto the container or its holder in the particular rotational position, until it is fixed on the product container.

It is advantageous in needle protection in accordance with the invention that the needle can be attached to the product container or its holder first and the needle is immediately protected by the needle protection, and that the product container does not have to be inserted into the injection device first and then the needle attached. Such a procedure is advantageous in the case of a double-chamber ampoule, in which the product to be administered is not mixed until just before it is administered, since subsequently placing the needle onto an ampoule which has already been inserted into the injection device could exert an additional pressure on the double-chamber ampoule which can have a disruptive effect on the mixing properties.

It is furthermore advantageous that, once a product container has been inserted into the casing of the injection device, a further casing part for protecting the injection needle or a user does not have to be added. The injection needle of the injection device is therefore protected during the entire process of exchanging the product container and the process of administering the product dosage.

Preferred embodiments are also disclosed in the sub-claims and by combining features from a number of sub-claims.

Preferred example embodiments of the invention are explained in the following by way of figures. Features disclosed by the example embodiment, each individually and in any combination of features, advantageously develop the subjects of the claims and also the embodiments described above. There is shown:

Figure 1 a distal part of an injection device in accordance with the invention, in an exploded view; Figure 2 the distal part of the injection device when assembled, including an assembled needle cover, wherein a needle cover of the injection device assumes an assembling position; Figure 3 the distal part of the injection device, wherein the needle cover assumes a protecting position; Figure 4 the distal part of the injection device, wherein the needle cover assumes an injection position. Figure 5 a partial cross-section of an embodiment of an injection device comprising a needle protection as set forth in the present invention, in an advanced position;

Figure 6 a partial cross-section of the embodiment of the injection device as set forth in Figure 5, in a retracted position; and

Figure 7 a partial cross-section of an embodiment of an injection device comprising a needle protection and a needle cap.

Figure 1 shows a distal part of an injection device in accordance with the invention, in an exploded view in which the separately produced components of the injection device are lined up along a central longitudinal axis L of the injection device, in an order suitable for being assembled. Figure 2 shows the same components, once assembled.

The distal part of the injection device includes a container holder 1 and a cladding structure 5 which when assembled, as for example can be seen from Figure 2, form the distal part of a casing of the injection device. The distal part of the injection device further includes a needle cover 15, and a restoring means 14 formed by a spiral spring which when assembled is axially pressurised between the container holder 1 and the needle cover 15 in each axial position of the needle cover 15. As may be seen in Figure 1 alone, but in particular in Figures 2 to 4, the needle cover 15 is accommodated, when assembled, in an annular space between a distal section of the container holder 1 and the cladding structure 5 surrounding said distal section, by the needle cover 15 protruding more or less deeply, depending on its axial position, into the annular space in the proximal direction.

The container holder 1 is substantially a simple cylindrical, preferably circular cylindrical, sleeve which forms a receptacle in its hollow cross-section for a container which contains a product to be injected. The container can in particular be formed like known medicine ampoules such as are known for example from diabetes therapy for accommodating insulin or also in other therapies, for example osteoporosis therapy. As can be seen for example from Figure 2, the container holder 1 forms a collar la in the region of its distal end 3, said collar la protruding radially inwards in the accommodating chamber and serving as a distal stopper for the product container to be inserted. Furthermore, the accommodating chamber forms an axial sliding guide for the container, which simultaneously also prevents tipping movements by the inserted container. The container holder 1 exhibits a narrower cross-section at its distal end 3 than in its other section. It is provided at its distal end 3 with an outer thread for a screw connection to a needle holder 10. It is provided at its proximal end with another outer thread which serves as a connection to a proximal casing part of the injection device. The proximal casing part mounts a conveying means for conveying the product and a dosing means, meshed with the conveying means, for pre-setting a product dosage which may be delivered by means of the conveying means. Suitable conveying means and dosing means are sufficiently known and therefore do not need to be described separately. A circumferential collar 2 of the container holder 1, projecting outwards, serves to support the spring 14 in the proximal direction.

The needle holder 10 which may be affixed to the distal end 3 of the container holder 1 is cup- shaped, with a sleeve part which is open in the proximal direction and at its distal end forms a base through which an injection needle 11 axially protrudes. In order to connect the needle holder 10 to the injection needle 11 over a larger axial length than would correspond to the axial thickness of the base, a cylindrical continuation projects from the centre of the base on its distal side, through which the injection needle 11 also protrudes. The injection needle 11 is held fixedly by the base of the needle holder 10 and the cylindrical continuation. A distal needle section protrudes freely from the distal end of the needle holder 10, i.e. from the cylindrical continuation, forming a distal needle tip 3. A proximal needle section protrudes into the hollow cross-section of the sleeve part of the needle holder 10, forming a proximal needle tip, as can best be seen in Figures 2 to 4. The needle holder 10 is provided with an inner protecting cap 12 and an outer protecting cap 13 by the manufacturer. The inner protecting cap 12 is plugged onto the cylindrical continuation of the needle holder 10. The outer protecting cap 13 is plugged onto the sleeve part of the needle holder 10. Once the outer protecting cap 13 has been removed, the injection needle 11 is still completely surrounded by the inner protecting cap 12 and thus protected from damage, and the user from a needle prick. The needle cover is substantially formed as a cylindrical, in the example embodiment circular cylindrical, sleeve. It exhibits a smooth outer surface area and an inner surface area formed in two stages, as may be seen from an overview of the figures, for example Figures 1 and 2. In its hollow cross-section, the needle cover 15 widens from a proximal section in one stage to a distal section. The distal and in particular the proximal section each comprise a cylindrical inner surface area. A swelling is thus obtained along the length of the proximal section, in which an annular gap 16 is formed which is open in the proximal direction. When assembled, the annular gap 16 accommodates a distal section of the spring 14 and serves as an axial guide for the spring 14. When assembled, the spring 14 is pressurised between the annular collar 2 and the distal end of the annular gap 16 of the needle cover 15. The container holder 1 thus forms a proximal mount, namely the annular collar 2, and the needle cover 15 a distal abutment, namely the distal end of the annular gap 16, for the spring 14. When assembled, the container holder 1 guides the needle cover 15 axially sliding. The distal, linearly cylindrical section of the container holder 1, which in Figure 1 is surrounded by the spring 14, serves as an axial sliding guide for the container holder 1. The guiding counter area is the surface inner area of the proximal section of the needle cover 15.

In the region of its proximal section, the needle cover 15 is provided with a locking element 17/18. A spring tongue 17 and a breach 18 of the spring tongue 17 combine to form said locking element 17/18. The spring tongue 17 is formed on the needle cover 15 as one piece. To form the spring tongue 17, two axial slits 19 are formed in an outer surface of the proximal section of the needle cover 15, said slits 19 extending up to the proximal end of the needle cover 15. The spring tongue 17 is elastically bendable in the radial direction and acts as a bending beam fixedly clamped on one side, namely at its distal end.

The cladding structure 5 forms a locking counter element 8 which, as may be seen in Figure 2, protrudes into the breach 18 in a proximal end position of the needle cover 15 and locks the needle cover 15 against moving in the distal direction, by a positive lock. The spring tongue 17 with its breach 18 and the locking counter element 8 are thus in a locking mesh, based on a positive lock, in the proximal end position of the needle cover 15. The positive lock is between a stopper area of the locking counter element 8, pointing in the proximal direction, and a counter stopper area, pointing in the distal direction and facing said stopper area, which forms the spring tongue 17 in the breach 18.

The locking counter element 8 is rigid, i.e. inflexible, with respect to the locking mesh. The locking mesh can, however, be released due to the elastic flexibility of the locking element 17/18, by elastically bending the locking element 17/18 radially inwards, out of the locking mesh.

For releasing the locking mesh, i.e. bending away the locking element 17/18, the injection device includes an unlocking element 7. The unlocking element 7 is inserted into a recess 6 which the needle cover 15 comprises on its surface outer area and protrudes through a breach 9 formed in the region of the recess 6. The unlocking element 7 comprises a pressure operating area pointing outwards and a projecting continuation with which it protrudes radially inwards through the breach 9 once it has been inserted into the recess 6. The cladding structure 5 forms the breach 6 at a location such that the breach 6 is radially arranged exactly above the locking element 17/18 when the injection device is assembled. The breach 9 id furthermore formed such that, when assembled, it comes to rest radially above a distal end section of the spring tongue 17. In the example embodiment, said distal end section of the spring tongue 17 is still situated distally from the breach 18, such that the entire axial length of the spring tongue 17 is available for elastically bending away and the radial pressure force of the unlocking element 7 necessary for bending away is as small as possible.

In order to assemble the injection device, the container holder 1 and the cladding structure 5 are connected to each other in the arrangement shown for example in Figure 2, such that the annular space for the needle cover 15 is obtained between them. The annular space is closed off in the proximal direction by the annular collar 2 and is open in the distal direction. The needle cover 15, together with the spring 14 inserted in the annular gap 16 of the needle cover 15, is then slid into the annular space formed between the container holder 1 and the cladding structure 5, up to the proximal end position shown in Figure 2. As it is slid in, the spring tongue 17 slides along the locking counter element 8 and is thus elastically bent away, radially inwards, until the breach 18 radially overlaps the locking counter element 8. As soon as the overlap is established, as is the case in the proximal end position of the needle cover 15, the spring tongue 17 elastically latches back again, radially outwards, and the locking mesh shown in Figure 2 is established.

Before the needle cover 15 is slid in, the unlocking element 7 is inserted into the recess 6 of the cladding structure 5, such that the continuation of the unlocking element 7 protrudes through the breach 9. The connection between the unlocking element 7 and the cladding structure 5 can be a frictional lock alone, but is preferably formed as a clip connection at an axial end of the unlocking element 7. In its connection to the cladding structure 5, the unlocking element 7 is clamped on one side like an elastic bending beam. The continuation, which protrudes radially inwards through the beach 9, is formed at the free end of said bending beam or unlocking element 7, and co-operates with the locking element 17/18 of the needle cover 15 for the purpose of releasing the locking mesh. It may be seen from Figure 2 how the unlocking element 7 is affixed in the manner of a bending beam. "D" indicates a pressure force using which the unlocking element 7 can be operated, radially inwards, in order to release the locking mesh. The continuation of the unlocking element 7, which acts on spring tongue 17 in order to release the locking mesh, has no contact with the spring tongue 17 when the unlocking element 7 is at rest, i.e. is not being operated, but exhibits a small radial distance from it.

Once the front part of the injection device shown has been connected to a rear part of the injection device which mounts the conveying means and the dosing means, the device is dispatched. The user has only still to insert the container filled with the product to be injected into the container holder 1 and to assemble the needle holder 10. This can be in the course of using the device for the first time or for example each time a used container is exchanged. The needle holder 10 can also be exchanged independently of exchanging the container.

In its proximal end position, the distal end of the needle cover 15 is sufficiently short of the distal end 3 of the container holder 1 that the needle holder 10 which the user grips in the region of its sleeve part can comfortably be connected to the container holder 1 by hand. Ideally, the needle cover 15 is at least sufficiently short of the distal end 3 of the container holder 1 that it allows lateral access to the needle holder 10 at least over the majority of the axial length of its sleeve part, when the needle holder 10 is connected to the injection device. To detach the needle holder 10, it can thus be gripped in the connecting region to the container holder 1, in the example embodiment in the region of the screw thread in the threaded mesh. When the needle holder 10 is assembled, the proximal needle section of the injection needle 11 pierces a sealing element which seals a distal end of the product container accommodated in the container holder 1. Assembling the needle holder 10 automatically fluidically connects the injection needle 11 to the interior of the product container. Since the proximal end position of the needle cover 15 has been selected such that when the needle cover 15 is assembled, the needle holder 10 can be assembled on the injection device and disassembled from the injection device, the proximal end position is referred to in the following as the assembling position of the needle cover 15. Once the needle holder 10 has been assembled, and still in the assembling position of the needle cover 15, the inner protecting cap 12 and the outer protecting cap 13 are removed from the needle holder 10, such that the injection needle 11 is exposed. Once the protecting caps 12 and 13 have been removed, the locking mesh of the locking elements 17/18 and 8 is released by pressure-operating the unlocking element 7 in the direction of the force arrow D, such that the needle cover 15 is moved in the distal direction up to a stopper, into its protecting position, by the influence of the elasticity force of the tensed spring 14. With the needle cover 15 situated in its protecting position, the injection device is then ready for an injection.

Figure 3 shows the injection device with the needle cover 15 situated in its protecting position. In the protecting position, the needle cover 15 protrudes beyond the tip of the injection needle 11. In the protecting position, the needle cover 15 can be locked against retracting in the proximal direction, such that it reduces unintentional access to the injection needle 11 from the side and thus damage to the injection needle 11 and in particular the danger of injury from the injection needle 11. If, in the protecting position, the needle cover 15 is locked against retracting, this locking mesh can however be released, in order to perform an injection. If a locking mesh is not provided in the protecting position and the needle cover in this case only serves as a blind, the injection device with the needle cover 15 situated in such a protecting position is immediately ready for a subsequent injection. This is to be implied for the example embodiment.

For the injection, the user selects the product dosage to be injected by means of the dosing means. The dosing means and the conveying means are meshed such that the selected dosage predetermines the product dosage which may be delivered in the next injection. Once the dosage has been selected, the injection device is placed onto the injection point via the distal end of the needle cover 15. By then pressing in the distal direction, the injection device is moved in the distal direction relative to the needle cover 15. In the course of this movement, the needle cover 15 slides on the sliding guide formed by the container holder 1 into the annular space between the container holder 1 and the cladding structure 5 and, conversely, the injection needle 11 advances in the distal direction beyond the needle cover 15, into the body tissue. The injection movement of the injection needle 11 is completed when the distal end of the needle holder 10 comes into contact with the surface of the skin, and the distal end of the needle cover 15 and the distal end of the needle holder 10 are correspondingly axially level. This state corresponds to the injection position of the needle cover 15.

Figure 4 shows the injection device with the needle cover 15 situated in its injection position. The injection needle 11 protrudes exactly beyond the needle cover 15 via its entire, free distal needle section. In the case of the injection described, it protrudes into the body tissue. The selected product dosage is then administered, by the user - preferably the patient him/herself - operating the conveying means. The conveying means can in particular include a piston accommodated in the container such that it can move axially in the distal direction and a piston rod acting on the piston. Correspondingly, in order to deliver or administer product, the user presses the piston rod in the distal direction and consequently advances the piston by a length predetermined by the elected dosage, thus delivering the selected product dosage from the container and administering it through the injection needle 11. Once the product dosage has been administered, the injection needle 11 is removed from the body tissue. Since the needle cover 15 is held in the injection position solely by the forces acting against each other on the needle cover 15, namely the elasticity force of the spring 14 and the pressure force acting against it, when the pressure force abates, the needle cover 15 moves in the distal direction back into the protecting position under the influence of the spring 14.

If the injection needle 11 is to be exchanged, the needle cover 15 is pressed beyond the injection position, back into the assembling position. In the last part of this movement, after the needle cover 15 has already been moved beyond the injection position in the proximal direction, the proximal end of the spring tongue 17 comes into contact with the locking counter element 8. The locking counter element 8 is tapered radially inwards on its side pointing in the distal direction, in the example embodiment its distal side simply points obliquely with respect to the axial. By tapering the locking counter element 8, the spring tongue 17 can slide along the locking counter element 8 via its proximal end and is thus continuously bent away radially inwards. As soon as the breach 18 draws axially level with the locking counter element 8, the spring tongue 17 latches back radially outwards again due to its inherent elasticity force and the locking mesh shown in Figure 2 is established. The needle holder 10 is again freely accessible from the side. Before disassembling the needle holder 10, at least one of the two protecting caps 12 and 13 should be plugged onto the needle holder 10, in order to prevent injuries from the injection needle 11. Only then should the needle holder 10, or as applicable the protecting cap 13 seated on the needle holder 10, be gripped and the needle holder 10 detached from the injection device.

Figures 5-7 also show the embodiment of an injection device comprising a needle protection in accordance with the invention. The needle cover is formed by the sleeve 15 which is arranged on the receptacle in form of a holder 4 for a product container, such that it can be shifted. Other arrangements of the sleeve are possible. Figure 5 shows the sleeve 15 in an advanced position in which it completely surrounds the injection needle 11 in the circumferential direction. The holder 4, together with the sleeve 15, can be inserted into the cladding structure 5 forming a casing of the injection device, and removed again from the casing 5 in order to exchange a product container. The injection needle 11 then remains protected by the sleeve 15 during the entire exchanging process. The sleeve 15 is held in the advanced position by a spiral spring 14, but can be shifted into a rear position, in which the injection needle 11 is exposed, as shown in Figure 6, by applying a force along the holder 4. To administer a product, the injection device is placed vertically on a surface at the injection point. When the injection needle 11 is injected into the surface, the sleeve 15 is retracted in the longitudinal direction of the holder and the injection needle can penetrate the surface. Once the injection device is removed from the surface, the sleeve 15 is returned to the advanced position again by the spiral spring 14. The injection needle therefore remains protected by the sleeve from exterior access during the entire administering process.

For exchanging the injection needle for a subsequent injection, a needle cap 13 serving as protecting cap can be placed onto the opening of the sleeve 15. When the needle cap is pushed in the longitudinal direction onto the injection device, the sleeve 15 serves as a guide for the needle cap 13 onto the injection needle until the cap is accommodating the needle within itself. The injection needle, together with the needle cap 13, can then be removed from the injection device. A new injection needle in another needle cap can correspondingly be placed onto the injection device by attaching the new needle cap to the sleeve 15 and guiding it towards the holder 4 or the product container using the sleeve 15, until it is fixed on it. The sleeve 15 is then shifted into a rear position. The injection needle remains protected, either by the sleeve or the needle cap, during the entire process of exchanging the injection needle and the process of exchanging a product container. Pricking injuries can therefore largely be prevented.

Claims

1. An injection device comprising a needle cover (15), said injection device including: a) a casing (1, 5) which forms a receptacle for a container containing an injectable product or forms said container itself; b) a conveying means for said product; c) a needle holder (10) comprising an injection needle (11) which is or can be connected fluidically to the container by means of said needle holder (10); d) and said needle cover (15) which is mounted by said casing (1, 5) such that it can be moved in the proximal direction, against a restoring force, from a protecting position, past an injection position, into an assembling position; e) wherein, in said protecting position, the needle cover (15) extends beyond a distal needle tip of said injection needle (11), and in said injection position is short of said needle tip; f) and wherein, in said assembling position, the needle cover (15) allows access to the needle holder (10), such that the needle holder (10) can be gripped and connected to the casing (1, 5) and/or detached from the casing (1, 5).

2. The injection device as set forth in the preceding claim, wherein in the assembling position, the needle cover (15) is short of a distal end of the needle holder (10) in the proximal direction.

3. The injection device as set forth in any one of the preceding claims, wherein the needle holder (10) is or can be connected to the casing (1, 5).

4. The injection device as set forth in any one of the preceding claims, wherein the casing (1, 5) includes a container holder (1) which forms an accommodating chamber for the container.

5. The injection device as set forth in the preceding claim, wherein the needle cover (15) is supported on said container holder (1) in the proximal direction.

6. The injection device as set forth in any one of the preceding two claims, wherein the container holder (1) guides the needle cover (15) sliding.

7. The injection device as set forth in any one of the preceding claims, further including a restoring means (14) which is elastically tensed at least in the injection position and assembling position and generates the restoring force acting on the needle cover (15) in the distal direction, as an elasticity force.

8. The injection device as set forth in the preceding claim, wherein the casing (1, 5) forms a mount (2) and the needle cover (15) an abutment (16) for said restoring means (14).

9. The injection device as set forth in the preceding claim, wherein one of said mount (2) or said abutment (16) axially guides the restoring means (14) formed as a mechanical spiral pressure spring.

10. The injection device as set forth in any one of the preceding claims, wherein the casing (1, 5) is provided with a first locking element (8) and the needle cover (15) is provided with a second locking element (17/18) and said locking elements (8, 17/18) are in a locking mesh in the assembling position of the needle cover (15), said locking mesh preventing the needle cover (15) from moving in the distal direction.

11. The injection device as set forth in the preceding claim, wherein the locking mesh is based on a positive lock between the locking elements (8, 17/18).

12. The injection device as set forth in any one of the preceding two claims, wherein at least one (17/18) of the locking elements (8, 17/18) can be moved, against an elasticity force, out of the locking mesh.

13. The injection device as set forth in the preceding claim, wherein the locking element (17/18) which can be moved, against the elasticity force, out of the locking mesh is elastic.

14. The injection device as set forth in the preceding claim, wherein said elastic locking element (17/18) bends elastically.

15. The injection device as set forth in any one of the preceding five claims, further including an unlocking element (7) which may be operated and, when operated, releases the locking mesh.

16. The injection device as set forth in the preceding claim, wherein said unlocking element (7) is a push-key.

17. The injection device as set forth in any one of the preceding two claims, wherein the unlocking element (7) presses against one of the locking elements (8, 17/18) to release the locking mesh.

18. The injection device as set forth in any one of the preceding three claims, wherein the unlocking element (7) acts on one of the locking elements (8, 17/18) through a breach (9) formed in the casing (1, 5) or in the needle cover (15), in order to release the locking mesh.

19. The injection device as set forth in any one of the preceding claims, wherein the casing (1, 5) includes a cladding structure (5) which surrounds at least an axial section of the needle cover (15) when the needle cover (15) is in the assembling position.

20. The injection device as set forth in the preceding claim, wherein the casing (1, 5) forms an annular space which accommodates the needle cover (15) over the majority of its axial length when the needle cover (15) is in the assembling position.

21. The injection device as set forth in any one of the preceding claims, wherein the needle cover (15) is moved into the injection position by a pressure force acting in the proximal direction on a distal end of the needle cover (15) and, when said pressure force abates, is automatically moved into the protecting position by the restoring force.

22. The injection device as set forth in any one of the preceding claims, further including a dosing means which meshes with the conveying means and when meshed performs a dosing movement, relative to the conveying means, which sets a product dosage which may be conveyed by means of the conveying means when the conveying means is operated.

23. A method for affixing a needle holder (10) holding an injection needle (11) to a distal end (3) of an injection device provided with a needle cover (15) which in a protecting position surrounds said injection needle (11) up to and beyond a distal needle tip when said needle holder (10) is affixed to said injection device and which can be moved from said protecting position, against a restoring elasticity force, towards a proximal end of the injection device beyond said distal end (3) of the injection device up to an assembling position, said method including the steps of: a) shifting said needle cover (15) from the protecting position into said assembling position and establishing a locking mesh which holds the needle cover (15) in the assembling position, against said elasticity force; b) affixing the needle holder (10) to the distal end (3) of the injection device while the needle cover (15) is held in the assembling position by said locking mesh; c) and releasing the locking mesh, such that the needle cover (15) moves into the protecting position due to the elasticity force.

24. A method for detaching a needle holder (10) holding an injection needle (11) from a distal end (3) of an injection device provided with a needle cover (15) which in a protecting position surrounds said injection needle (11) up to and beyond a distal needle tip when said needle holder (10) is affixed to said injection device and which can be moved from said protecting position, against a restoring elasticity force, towards a proximal end of the injection device beyond said distal end (3) of the injection device up to an assembling position, said method including the steps of: a) shifting said needle cover (15) from the protecting position into said assembling position and establishing a locking mesh which holds the needle cover (15) in the assembling position, against said elasticity force; b) detaching the needle holder (10) from the distal end (3) of the injection device while the needle cover (15) is held in the assembling position by said locking mesh.

25. The method as set forth in the preceding claim, wherein a protecting cap (12; 13) for the injection needle (11) is affixed to the needle holder (10) once the locking mesh has been established and before the needle holder (10) is detached.

26. An injection device for administering a fluid product, comprising a casing (5), a holder (4) for a product container of said fluid product, an injection needle (11), and a needle protector, wherein said needle protector comprises a sleeve (15) arranged on one of said holder or said product container such that it can shift and generally surrounds said injection needle in an advanced position.

27. The injection device as set forth in claim 26, wherein a spring (14) holds said sleeve in said advanced position.

28. The injection device as set forth in claim 26, wherein a guiding means is provided to guide when the injection needle (11) is placed onto or removed from the product container.